Comparison of microRNA expression profiles in HCC-derived microvesicles and the parental cells and evaluation of their roles in HCC.

To determine whether the microRNAs (miRNAs) contained in cancer-derived microvesicles (MVs) mirror those of the parental tumor cells, we compared the miRNA expression profiles of MVs derived from their parental hepatocellular carcinoma (HCC) cells. The presence and levels of 888 miRNAs from SMMC-7721 cells and MVs were detected by Agilent miRNA microarray analysis. Four selected miRNAs were verified by real time qRT-PCR. Furthermore, the genes of the miRNAs were bioinformatically identified to explore potential roles of the miRNAs in HCC microenvironment. Our results showed that miRNAs expression profiles of MVs derived from HCC were significantly changed. Of all the miRNAs tested, 148 miRNAs were co-expressed in MVs and SMMC-7721 cells, only 121 and 15 miRNAs were detected in MVs and SMMC-7721 cells, respectively. Among the 148 co-expressing miRNAs, 48 miRNAs had the similar expression level and 6 of them were supposed to be oncogenic or suppressive miRNAs. According to the target prediction by Quantile Algorithm method, these miRNAs may regulate 3831 genes which were closely related to cell cycle, apoptosis and oncogenesis, and 78 were known tumor suppressors or oncogenes. Gene ontology (GO) analysis indicated that 3831 genes were mainly associated with nucleic acid binding, cell death, cell adhesion. MVs containing miRNAs, released into the HCC microenvironment, bear the characteristic miRNAs of the original cells and might participate in cancer progression.